Measuring physical and biochemical parameters with mobile devices

ABSTRACT

A method for a mobile computing device with a camera and a screen to measure a test strip in a test strip module includes, in a calibration phase before a sample is introduced to a reaction area on the test strip, detecting with the camera an ambient light effect when the test strip module is mounted on the face of the mobile computing device. In a measurement phase after the sample is introduced to the reaction area on the test strip, the method also includes illuminating the test strip with a light provided by a light source area on the screen, detecting with the camera one or more colors of the reaction area, correcting the detected one or more colors for the ambient light effect, correlating the corrected one or more colors to an analyte property, and displaying a value of the analyte property on the screen.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation under 35 U.S.C. § 120 of U.S. patentapplication Ser. No. 14/528,100, filed Oct. 30, 2014, which claims thebenefit of U.S. Provisional Application No. 61/940,500, filed Feb. 17,2014, U.S. Provisional Application No. 61/944,306, filed Feb. 25, 2014,U.S. Provisional Application No. 62/025,883 filed Jul. 17, 2014, andU.S. Provisional Application No. 62/044,886 filed Sep. 2, 2014. The U.S.Patent Application and the U.S. Provisional Applications, including anyappendices or attachments thereof, are incorporated by reference hereinin their entirety.

FIELD

The present disclosure generally relates to methods and systems forphotometric analysis an analyte on a test strip

BACKGROUND

A specimen test strip has a reaction area containing reagents that reactwith an analyte in a specimen sample, such as cholesterol or glucose ina blood sample. The reaction area changes color according to a propertyof the analyte, such as the cholesterol or glucose level in blood. Thespecimen test strip is inserted into a meter that optically determinesthe characteristic of the analyte.

SUMMARY

In examples of the present disclosure, a method for a mobile computingdevice with a camera and a screen to measure a test strip in a teststrip module is disclosed. The method includes, in a calibration phasebefore a sample is introduced to a reaction area on the test strip,detecting with the camera an ambient light effect when the test stripmodule is mounted on the face of the mobile computing device. In ameasurement phase after the sample is introduced to the reaction area onthe test strip, the method also includes illuminating the test stripwith a light provided by a light source area on the screen, detectingwith the camera one or more colors of the reaction area, correcting thedetected one or more colors for the ambient light effect, correlatingthe corrected one or more colors to an analyte property, and displayinga value of the analyte property on the screen.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present disclosure will becomemore fully apparent from the following description and appended claims,taken in conjunction with the accompanying drawings. These drawingsdepict only several embodiments in accordance with the disclosure andare therefore not to be considered limiting of its scope. The disclosurewill be described with additional specificity and detail through use ofthe accompanying drawings.

In the drawings:

FIG. 1 illustrates a top isometric view of a test strip module to beused with a mobile computing device in examples of the presentdisclosure;

FIG. 2 illustrates a bottom isometric view of the test strip module ofFIG. 1 in examples of the present disclosure;

FIG. 3 illustrates a cross-sectional view of the test strip module ofFIG. 1 on the mobile computing device of FIG. 1 in examples of thepresent disclosure;

FIG. 4 illustrates a variation of the test strip module of FIG. 1 inexamples of the present disclosure;

FIG. 5 illustrates a variation of the test strip module of FIG. 1 inexamples of the present disclosure;

FIG. 6 is a cross-sectional view of a test strip module with inner andouter compartments in examples of the present disclosure;

FIG. 7 is a cross-sectional view of a test strip module with a skirt inexamples of the present disclosure;

FIG. 8 is a cross-sectional view of a test strip module with a skirt inexamples of the present disclosure;

FIG. 9 is a cross-sectional view of a test strip module with a positionanchor on a skirt in examples of the present disclosure;

FIG. 10 is a cross-sectional view of a test strip module with a fine orpliant bottom interface to a face of a mobile computing device inexamples of the present disclosure;

FIG. 11 is a cross-sectional view of a test strip module with a slantedsample channel in examples of the present disclosure;

FIG. 12 is a cross-sectional view of a test strip module with a sampleobservation window in examples of the present disclosure;

FIG. 13 is a top view of a test strip package in examples of the presentdisclosure;

FIG. 14 is a top view of a screen protector with a slot to receive atest strip module in examples of the present disclosure;

FIG. 15 is a top isometric view of a protective case with a slot toreceive a test strip module in examples of the present disclosure;

FIG. 16 is a flowchart of a method for a photometric test strip analyzerexecuted by a processor in the mobile computing device of FIG. 1 todetermine an analyte property from a test strip in a test strip modulein examples of the present application;

FIG. 17 illustrates limiting a notification to a specific edge of themobile computing device of FIG. 1 in examples of the present disclosure;

FIG. 18 is flowchart of a method for implementing a measurement pre-testin the method of FIG. 16 in examples of the present disclosure;

FIG. 19 shows a test strip in examples of the present disclosure;

FIG. 20 is flowchart of a method for implementing a calibration and ameasurement in the method in FIG. 16 in examples of the presentdisclosure;

FIG. 21 illustrates a combined chart plotting light intensity and cameraresponse in a calibration phase and a measurement phase in examples ofthe present disclosure;

FIGS. 22 and 23 show how a test strip module may be shielded in examplesof the present disclosure;

FIG. 24 is a chart that plots color values over ambient light levels fordifferent values of an analyte property in examples of the presentdisclosure;

FIG. 25 is an isometric view of a variation of the test strip module ofFIG. 1 in examples of the present disclosure; and

FIG. 26 is an enlarged cross-sectional view of the test strip module ofFIG. 25 in examples of the present disclosure.

DETAILED DESCRIPTION

As used herein, the term “includes” means includes but not limited to,the term “including” means including but not limited to. The terms “a”and “an” are intended to denote at least one of a particular element.The term “based on” means based at least in part on. The term “or” isused to refer to a nonexclusive such that “A or B” includes “A but notB,” “B but not A,” and “A and B” unless otherwise indicated.

FIG. 1 illustrates a top isometric view of a test strip module 100 to beused with a mobile computing device 102 in examples of the presentdisclosure. Mobile computing device 102 has a camera 104, an ear speaker106, and a screen 108 on a face 110 (e.g., a front face) of mobilecomputing device 102. On face 110, camera 104 may be located above earspeaker 106. Ear speaker 106 may have the form of a hole (as shown) or aprotrusion above face 110 (not shown). Mobile computing device 102includes a processor 112, a nonvolatile memory 114, and a volatilememory 116. Nonvolatile memory 114 stores the code for a photometrictest strip analyzer 117. Mobile computing device 102 may be a mobilephone, a tablet computer, or a laptop computer. Hereafter a “mobilephone 102” is used to represent variations of mobile computing device102.

FIG. 2 illustrates a bottom isometric view of test strip module 100 inexamples of the present disclosure. Test strip module 100 has a case 202with an open bottom, a test strip 204 (shown in phantom) held insidecase 202, and a bottom cover 206 that closes the open bottom of case202. Case 202 has a bottom surface 207 and bottom cover 206 has a bottomsurface 208 that may or may not be even with bottom surface 207 of case202. Bottom cover 206 also has a position feature 210, which may be aposition anchor that extends down past a mating surface of test stripmodule 100 to face 110 of mobile phone 102. The mating surface may bebottom surface 207 or 208. Position anchor 210 has a shape matching acorresponding feature on face 110 (FIG. 1) of mobile phone 102 (FIG. 1),such as ear speaker hole 160 (FIG. 1). Position anchor 210 may have arectangular or an obround shape.

Bottom cover 206 defines a light port 212 and a camera port 214. Lightport 212 allows light emitted by a light source area 118 (FIG. 1) ofscreen 108 to enter test strip module 100 and illuminate the interior oftest strip module 100, including a reaction area on test strip 204.Camera port 214 allows camera 104 (FIG. 1) of mobile phone 102 tocapture images inside test strip module 100, including the reaction areaon test strip 204. Camera port 214 may be located above position anchor210 to match the configuration of camera 104 and a feature correspondingto position anchor 210 on mobile phone 102, such as ear speaker hole106. Light port 212 and camera port 214 may be holes or windows.

FIG. 3 illustrates a cross-sectional view of test strip module 100 onmobile phone 102 in examples of the present disclosure. In use, a userrests mobile phone 102 flat on a horizontal surface and places teststrip module 100 on face 110 of mobile phone 102. The user then slidestest strip module 100 around on face 110 until position anchor 210engages the corresponding feature on face 110, such as fitting into earspeaker hole 106. When position anchor 210 fits into ear speaker hole106, mating surface 207 or 208 may come into intimate contact with face110, and camera port 214 and light port 212 become properly aligned withcamera 104 and light source area 118, respectively. Note the exact shapeand location of position anchor 210 depends on the configuration ofcamera 104 and ear speaker 106 of mobile phone 102.

FIG. 4 illustrates a variation 400 of test strip module 100 (FIG. 1) inexamples of the present disclosure. Test strip module 400 is similar totest strip module 100 except position anchor 210 has been replaced by aposition anchor 410 at a different location to match the location of acorresponding feature, such as the ear speaker hole, on the face ofanother mobile phone.

FIG. 5 illustrates a variation 500 of test strip module 100 (FIG. 1) inexamples of the present disclosure. Test strip module 500 is similar totest strip module 100 except position anchor 210 has been replaced by aposition feature 510, which may be a position hole defined by bottomcover 206. Position hole 510 matches the configuration of acorresponding feature, such as a protruding ear speaker, on the face ofanother mobile phone. In use, a user slides test strip module 500 aroundon the face of the mobile phone until position hole 510 engages thecorresponding feature on the face of the mobile phone, such as receivingthe ear speaker protrusion. When position hole 510 receives the earspeaker protrusion, mating surface 207 or 208 may come into intimatecontact with the face of the mobile phone, and camera port 214 and lightport 212 become properly aligned with the camera and the light sourcearea on the face of the mobile phone, respectively.

FIG. 6 is a cross-sectional view of a test strip module 600 in examplesof the present disclosure. Test strip module 600 may be a variation ofanother test strip module in the present disclosure so test strip module600 may share elements with the other test strip module. Test stripmodule 600 has a case 602 with an open bottom, an inner compartment 604,and an outer compartment 606 that surrounds at least part of innercompartment 604. Test strip 204 is located in inner compartment 604 andouter compartment 606 shields test strip 204 from ambient light 610 thatmay leak in through an interface 611 between a perimeter wall 612 ofcase 602 and face 110 of mobile phone 102 onto which test strip module600 is placed. Outer compartment 606 traps and absorbs ambient light 610so ambient light 610 does not illuminate test strip 204 in innercompartment 604. Outer compartment 606 may have a texture or be formedof a material that absorbs light. Without outer compartment 606, ambientlight 610 may interfere with the expected illumination from light sourcearea 118 (FIG. 3) of screen 108 on face 110.

FIG. 7 is a cross-sectional view of a test strip module 700 in examplesof the present disclosure. Test strip module 700 may be a variation ofanother test strip module in the present disclosure so test strip module700 may share elements with the other test strip module. Test stripmodule 700 has a case 702 with a perimeter wall 712 and a skirt 704around at least part of perimeter wall 712. Test strip 204 is located incase 702 and skirt 704 shields test strip 204 from ambient light 710that may leak in through an interface 711 between perimeter wall 712 andface 110 of mobile phone 102 onto which test strip module 700 is placed.Skirt 704 may lie flat against face 110 of mobile phone 102. Skirt 704traps and absorbs ambient light 710 so ambient light 710 does notilluminate test strip 708. Skirt 704 may have a texture or be formed ofa material that absorbs light. Without skirt 704, ambient light 710 mayinterfere with the expected illumination from light source area 118(FIG. 3) of screen 108 on face 110.

In some examples of the present disclosure, skirt 704 is a slide engagedto case 702. Skirt 704 may be initially stored in a retracted positioninside case 702 (shown in phantom). In use, skirt 704 may slide out fromthe retracted position to an extended position outside of case 702.

FIG. 8 is a cross-sectional view of a test strip module 800 in examplesof the present disclosure. Test strip module 800 is similar to teststrip module 700 except skirt 704 is now hinged to perimeter wall 712 ofcase 702. Skirt 704 may be initially stored in an upright positionagainst perimeter wall 712 of case 702 (shown in phantom). In use, skirt704 may rotate from the upright position to a horizontal positionagainst face 110 of mobile phone 102 onto which test strip module 800 isplaced.

FIG. 9 is a cross-sectional view of a test strip module 900 in examplesof the present disclosure. Test strip module 900 may be a variation ofanother test strip module in the present disclosure so test strip module900 may share elements with the other test strip module. Test stripmodule 900 has a skirt 904 around at least part of perimeter wall 712 ofcase 702. Skirt 904 may be similar to skirt 704 (FIG. 7 or 8). Insteadof a bottom cover with a position anchor or position hole, skirt 904 hasa position anchor 920 that extends downward from skirt 904 and fits intoa matching hole 922 on a face 924 of a portable computing device 926.Alternatively skirt 904 defines a position hole (not shown) thatreceives a matching protrusion (not shown) on face 924.

FIG. 10 is a cross-sectional view of a test strip module 1000 inexamples of the present disclosure. Test strip module 1000 may be avariation of another test strip module in the present disclosure so teststrip module 600 may share elements with the other test strip module.Test strip module 1000 includes a case 1002 with a perimeter wall 1012.Perimeter wall 1012 has a bottom interface 1024 that comes into intimatecontact with face 110 of portable computing device 102 to preventambient light from entering through any gap between bottom interface1024 and face 110. In some examples, bottom interface 1024 is sanded orotherwise processed smooth to have a roughness of 100 microns. In otherexamples, bottom interface 1024 may be a pliant material, such as apolyurethane soft-touch coating, fixed to the body of perimeter wall1012.

FIG. 11 is a cross-sectional view of a test strip module 1100 inexamples of the present disclosure. Test strip module 1100 may be avariation of another test strip module in the present disclosure so teststrip module 1100 may share elements with the other test strip module.Test strip module 1100 includes case 202 with the open bottom, teststrip 204 held inside case 202, and bottom cover 206 that closes theopen bottom of case 202. Case 202 defines a sample (e.g., blood) channel1104 from the exterior to the interior of case 202, such as from a roof1106 to a ceiling 1108. Sample channel 1104 is sloped relative to matingsurface 207 or 208. Sample channel 1104 has an upper end 1112 with aninlet and a lower end 1114 with an outlet. A sample enters the inlet atupper end 1112, travels through sample channel 1104, exits through theoutlet at lower end 1114, and enters a reaction area 1116 on test strip204.

Sample channel 1104 is oriented so lower end 1114 is located in orproximate to a first end 1115 of test strip module 1100 with test strip204 and camera port 214, and upper end 1112 is located in or proximateto a second end 1113 of test strip module 1100 with camera port 214.First end 1115 may be a distal end away from a user while second end1113 may be a proximate end close to the user. When ambient light 1118is coming from the front (or the side) of a user during use, an ambientlight 1118 would be misaligned with sample channel 1104 and thereforeunable to enter test strip module 1100 through sample channel 1104. Whenan ambient light 1120 is coming from the back of the user, ambient light1120 would be blocked by the user and therefore unable to enter teststrip module 1100 through sample channel 1104.

FIG. 12 is a cross-sectional view of a test strip module 1200 inexamples of the present disclosure. Test strip module 1200 may be avariation of another test strip module in the present disclosure so teststrip module 1200 may share elements with the other test strip module.Test strip module 1200 includes a case 1201 with an open bottom, a teststrip 1202 located both inside and outside of case 1201, and bottomcover 206 that closes the open bottom of case 1201. Test strip 1202 hasa tip 1204 located outside of case 1201 to receive a sample, and areaction area 1206 and a reservoir 1208 located inside case 1201. Thesample travels to reaction area 1206, and a part of the sample travelsfurther downstream to reservoir 1208. Case 1201 includes an observationwindow 1210 to reservoir 1208. When a user sees the sample inobservation window 1210, the user knows test strip 1202 has receives asufficient sample amount.

FIG. 13 is a top view of a test strip package 1300 in examples of thepresent disclosure. Test strip package 1300 includes multiple test stripmodules, such as test strip modules 1302-1, 1302-2, 1302-3, 1302-4, and1302-5 (collectively as “test strip modules 1302” or individually as ageneric test strip module “1302”). Each test strip module 1302 may besimilar to any test strip module described in the present disclosure.Test strip modules 1302 may share a common case and a common bottomcover. The case may have multiple compartments that each holds a teststrip. The case is slidably engaged with the bottom cover. The bottomcover defines a camera port and a light port. The bottom cover has aposition feature, such as a position anchor or hole, that engages amatching feature, such as an ear speaker hole or protrusion, on face 110of mobile phone 102 to align the camera port and the light port on thebottom cover to camera 104 (FIG. 1) and light source area 118 (FIG. 1)on screen 108 (FIG. 1) of mobile phone 102.

The case may slide over the bottom cover to place one compartment at atime over the camera port and the light port as shown in FIG. 13. Theposition of the compartment over the camera port and the light port maybe defined by latching mechanism, such as snap fit protrusions anddepressions, on the case and the bottom cover. When one compartment isin position, the adjacent compartment or compartments may shield thatcompartment from ambient light.

FIG. 14 is a top view of a screen protector 1400 for mobile phone 102 inexamples of the present disclosure. Screen protector 1400 defines a slotor cutout 1402 to receive and position a test strip module 1404 overcamera 104 (FIG. 1) and light source area 118 (FIG. 1) on screen 108 ofmobile phone 102. Test strip module 1404 may be any test strip moduledescribed in the present disclosure.

FIG. 15 is a top isometric view of a protective case 1500 for mobilephone 102 in examples of the present disclosure. Protective case 1500defines a slot or cutout 1502 to receive and position a test stripmodule 1504 over camera 104 (FIG. 1) and light source area 118 (FIG. 1)on screen 108 of mobile phone 102. Test strip module 1504 may be any ofthe test strip modules described in the present disclosure.

FIG. 16 is a flowchart of a method 1600 for photometric test stripanalyzer 117 (FIG. 1) executed by processor 112 (FIG. 1) on mobile phone102 to determine an analyte property (e.g., cholesterol or glucoselevel) from a test strip in a test strip module (e.g., test strip 204 intest strip module 100 in FIG. 1) in examples of the present application.Method 1600 may include one or more operations, functions, or actionsillustrated by one or more blocks. Although the blocks of method 1600and other methods described herein are illustrated in sequential orders,these blocks may also be performed in parallel, or in a different orderthan those described herein. Also, the various blocks may be combinedinto fewer blocks, divided into additional blocks, or eliminated basedupon the desired implementation. Method 1600 may begin in block 1602.

In block 1602, processor 112 receives user input to run photometric teststrip analyzer 117. In response processor 112 executes the code forphotometric test strip analyzer 117. Block 1602 may be followed by block1604.

In block 1604, processor 112 limits notifications (e.g., banners) onmobile phone 102 to a location away from light source area 118 (FIG. 1)on screen 108 (FIG. 1).

FIG. 17 illustrates a banner 1702 that would normally appear at a short,top edge of mobile phone 102 in examples of the present disclosure. Ascan be seen, banner 1702 would supersede light source area 118 alsolocated on the short, top edge of screen 108. To avoid this, processor112 locks mobile phone 102 in a landscape orientation even thoughphotometric test strip analyzer 117 is actually running in a portraitorientation so banner 1702 appears at a long, side edge of screen 108.In other examples, processor 112 may change banner 1702 to an alert thatappears in the middle of screen 108 instead of the short, top edge ofscreen 108. In other examples, when an operating system (OS) of mobilephone 102 permits, processor 112 may temporarily turn off or postponenotifications for other applications.

Referring back to FIG. 16, block 1604 may be followed by block 1606.

In block 1606, processor 112 performs a measurement pre-test todetermine if mobile phone 102 is has the proper setup to determine theanalyte property. Block 1606 may be followed by block 1608.

In block 1608, processor 112 determines if mobile phone 102 has passedthe measurement pre-test. If not, block 1608 may be followed by block1610. Otherwise block 1608 may be followed by block 1612.

In block 1610, processor 112 suggests changing the setup of mobile phone102 by displaying a message on screen 108.

FIG. 18 is flowchart of a method 1800 for implementing blocks 1606,1608, and 1610 of method 1600 in examples of the present disclosure.Method 1800 may begin in block 1802 following block 1604 in method 1600.

In block 1802, processor 112 determines if an airplane mode is turned onfor mobile phone 102. In the airplane mode, wireless connections andservices are turned off so mobile phone 102 does not receive calls thatwould otherwise interrupt photometric test strip analyzer 117 (FIG. 1)and change the color of the light provided by light source area 118(FIG. 1). If mobile phone 102 is not in the airplane mode, block 1802may be followed by block 1804. Otherwise block 1802 may be followed byblock 1806.

In block 1804, processor 112 suggests turning on the airplane mode bydisplaying a message on screen 108. Processor 112 may exit photometrictest strip analyzer 117 or loop back to block 1802 to determine if theuser has turned on the airplane mode. Alternatively processor 112 mayautomatically turn on the airplane mode and proceed to block 1806.

In block 1806, processor 112 determines if a battery capacity of mobilephone 102 is greater than a threshold. The threshold ensures mobilephone 102 has sufficient energy to determine the analyte property. Ifthe battery capacity of mobile phone 102 is not greater than thethreshold, block 1806 may be followed by block 1808. Otherwise block1806 may be followed by block 1810.

In block 1808, processor 112 suggests charging mobile phone 102 bydisplaying a message on screen 108. Processor 112 may exit photometrictest strip analyzer 117 or loop back to block 1806 to determine if thebattery capacity is now greater than the threshold.

In block 1810, processor 112 determines if mobile phone 102 is runningon an internal battery. When mobile computing device 102 is plugged intoa wall socket, power fluctuation in the mains may vary the lightprovided by light source area 118 (FIG. 1) of screen 108 (FIG. 1) andsensor response of camera 104 (FIG. 1). If mobile phone 102 is notrunning on the internal battery, block 1810 may be followed by block1812. Otherwise block 1810 may be followed by block 1814.

In block 1812, processor 112 suggests unplugging mobile phone 102 fromthe wall socket by displaying a message on screen 108. Processor 112 mayexit photometric test strip analyzer 117 or loop back to block 1810 todetermine if mobile phone 102 is now running on the internal battery.

In block 1814, processor 112 determines if an ambient light level isless than a threshold. When the ambient light level is high, it may leakinto test strip module 100 and interfere with the light provided bylight source area 118 of screen 108. Processor 112 may sense the ambientlight level using camera 104, which is not covered by any test stripmodule at this point, and optionally record it for further use in themeasurement phase. If the ambient light level is not less than thethreshold, block 1814 may be followed by block 1816. Otherwise block1814 may be followed by block 1612 in method 1600.

In block 1816, processor 112 suggests moving or shielding mobile phone102 by displaying a message on screen 108. Processor 112 may exitphotometric test strip analyzer 117 or loop back to block 1814 todetermine if the ambient light level is now less than the threshold.

Referring back to FIG. 16, in block 1612, processor 112 detects teststrip 204 in test strip module 100 after test strip module 100 is placedon mobile phone 102. Processor 112 detects test strip 204 by usingcamera 104 to capture an image of the interior of test strip module 100and light source area 118 illuminating the interior of test strip module100, and finding a candidate in the image that resembles test strip 204based on shape, color, or color intensity.

FIG. 19 shows test strip 204 in examples of the present disclosure. Teststrip 204 includes a reaction area 1902 and a color calibration area904. Reaction area 1902 may include subareas 1906-1, 1906-2, and 1906-3(collectively as “subareas 1906”) targeting different value ranges of ananalyte property or properties of different analytes. Subareas 1906 mayhave the same color or different colors before a sample is introduced.Color calibration area 1904 may have a known color or color intensity,or include subareas of known colors or color intensities.

Once processor 112 (FIG. 1) find a candidate in the image that resemblestest strip 204, processor 112 takes a cross-section 1908 of an areawhere reaction area 1902 should be located on the candidate anddetermines if cross-section 1908 includes sections with different colorsmatching the different colors of subareas 1906-1, 1906-2, and 1906-3.

Referring back to FIG. 16, in block 1614, processor 112 determines iftest strip 204 is correctly positioned. Test strip 204 is aligned withcamera 104 and light source area 118 when cross-section 1908 includesthe different color sections matching the different colors of subareas1906. If not, block 1614 may be followed by block 1616. Otherwise block1614 may be followed by block 1618.

In block 1616, processor 112 suggests moving test strip module 100 bydisplaying a message on screen 108. Processor 112 may loop back to block1612 to determine if test strip 204 is now correctly positioned.

In block 1618, processor 112 locks a white balance setting of camera 104to a known value. When an OS of mobile phone 102 does not allowprocessor 112 to set the white balance setting, processor 112 maytemporarily lock the white balance setting to the known value by causingcamera 104 to capture a first image under low light (e.g., with lightsource area 118 turned off) and then immediately capturing a secondimage under normal lighting (e.g., with light source area 118 turnedon). In a short period of time immediately after camera 104 captures thefirst image under low light, the white balance setting will remain atthe known value so the second image is also captured at this know whitebalance setting. For example, the white balance setting under low lightmay provide a 1:1:1 red, green, and blue (RGB) ratio. Block 1618 may befollowed by block 1620.

In block 1620, processor 112 performs a calibration of a lightingcondition inside test strip module 100. Block 1620 may be followed byblock 1622.

In block 1622, processor 112 determines if the lighting condition insidetest strip module 100 passed the calibration. If not, block 1622 may befollowed by block 1624. Otherwise block 1622 may be followed by block1626.

In block 1624, processor 112 suggests moving mobile phone 102 orshielding test strip module 100 by displaying a message on screen 108.Processor 112 may loop back to block 1620 to determine if the lightingcondition inside test strip module 100 now passes the calibration.

In block 1626, processor 112 performs a measurement of test strip 204.In the measurement, processor 112 uses camera 104 to capture an image ofa reaction area on test strip 204, determines one or more colorcharacteristics of the reaction area, corrects the one or more colorcharacteristics, correlates the corrected one or more colorcharacteristics to the analyte property. Block 1626 may be followed byblock 1628.

In block 1628, processor 112 displays the result on screen 108.

FIG. 20 is flowchart of a method 2000 for implementing blocks 1620,1622, 1624, and 1626 of method 1600 in examples of the presentdisclosure. Method 2000 may begin in block 2001 following block 1618 inmethod 1600.

In block 2001, processor 112 enters a calibration phase and uses camera104 to capture a series of images under light of a certain pattern andincrementing intensities provided by light source area 118. Light sourcearea 118 increments from off to fully on. In some examples, the lightintensities include 0, 0.2, 0.4, 0.6, 0.8, and 0.9. In other examplesthe incrementing light intensities include only 0 and 0.9. The lightpattern may square, triangular, or another shape that evenly illuminatestest strip 204 (e.g., FIG. 19) due to the interior geometry of teststrip module 100. Block 2001 may be followed by block 2002.

In block 2002, processor 112 linearizes the camera's response for allcolor channels based on the images captured in block 2001. Image sensorsof camera 104 may have non-linearity at the extremes of their range.Linearizing the camera's response corrects the non-linearity to provideactual color channel values. Block 2002 may be followed by block 2004.

In block 2004, processor 112 determines an ambient light effect based oncolor calibration area 1904 (e.g., FIG. 19) of test strip 204 capturedon a first image taken with light source area 118 off (e.g., lightintensity=0) and a second image taken with light source area 118 on(e.g., light intensity=0.9) in the series of images. Color calibrationarea 1904 has an actual color channel value that is known to processor112.

FIG. 21 illustrates a combined chart 2100 with an upper chart plottinglight intensity over time and a lower chart plotting a camera responsefor a color channel over the same time in a calibration phase and ameasurement phase in examples of the present disclosure. The values inchart 2100 are provided for illustrative purposes. The camera responsemay be an average of the color channel values of areas in the first andthe second images that correspond to color calibration area 1904 with aknown color channel value.

In the example calibration phase, the camera response has a colorchannel value of C_(off) when light source area 118 is off (e.g., lightintensity=0) due to ambient light leaking into test strip module 100.The camera response has a value of C_(on) when light source area 118 ison (e.g., light intensity is 0.9). The following formula may be used todetermine a corrected color channel value without the ambient lighteffect:

${C_{corrected} = {\left( {C_{detected} - C_{on}} \right)\frac{C_{actual}}{C_{on} - C_{off}}}},{or}$${C_{corrected} = {\left( {C_{detected} - C_{off}} \right)\;\frac{C_{actual}}{C_{on} - C_{off}}}},$where C_(off) is the detected color channel value of color calibrationarea 1904 with light source area 118 off during the calibration phase,C_(on) is the detected color channel value of color calibration area1904 with light source area 118 on during the calibration phase,C_(actual) is the actual color channel value of color calibration area1904, C_(detected) is the detected color channel value of a desired area(e.g., reaction area 1902 in FIG. 19) with light source area 118 onduring the measurement phase, and C_(corrected) is the corrected colorchannel value of the desired area during measurement phase.

Referring back to FIG. 20, block 2004 may be followed by block 2006.

In block 2006, processor 112 determines if the ambient light effect isgreater than a threshold. The ambient light effect is represented bydetected color channel value C_(detected) with light source area 118 offduring the calibration phase. A high ambient light effect may result indetected color channel values that cannot be corrected. When the ambientlight effect is greater than the threshold, block 2006 may be followedby block 2008. Otherwise block 2006 may be followed by block 2010.

In block 2008, processor 112 suggests moving mobile phone 102 orshielding test strip module 100 by displaying a message on screen 108.

FIGS. 22 and 23 show how test strip module 100 may be shielded inexamples of the present disclosure. In FIG. 22, a user places her hand2202 over test strip module 100 to shield it from the ambient light. InFIG. 23, the user places a box top 2302 over test strip module 100. Boxtop 2030 may be part of the packaging for test strip module 100.

Referring back to FIG. 20, processor 112 may loop back to block 2001recalibrate camera 104.

In block 2010, processor 112 enters the measurement phase and causesmobile phone 102 to vibrate after the sample is introduced to a sampleinlet on test strip module 100. The vibration helps to move the samplethrough sample channel 1104 (FIG. 11) to test strip 204. Block 2010 maybe followed by block 2012.

In block 2012, processor 112 captures at least one image of reactionarea 1902 on test strip 204 with light source area 118 on and detects atleast one color characteristic of the reaction area. In some examples ofthe present disclosure, processor 112 captures two images of reactionarea 1902 at times T1, T2 and detects two colors C1, C2 of reaction area1902 as shown in FIG. 21. Block 2012 may be followed by block 2014. Insome examples, processor 112 captures one image of the reaction area1902 at T3 and detects a color C3 of reaction area 1902 as shown in FIG.21.

In block 2014, processor 112 corrects the detected color or colors toremove the ambient light effect in their values. Block 2014 may befollowed by block 2016.

In block 2016, processor 112 correlates the corrected color or colors tothe analyte property. In the examples with two corrected colors,processor 112 determines a slope of the line between a first point (C1,T1) and a second point (C2, T2) and correlates the slope to the analyteproperty from a chart mapping slopes to analyte property values.

In some examples of the present disclosure, processor 112 does notcorrect the color of the reaction area by removing the ambient lighteffect. Instead processor 112 uses the known color or colors of colorcalibration area 1904 and the detected color or colors of calibrationarea 1904 to rescale a detected color of reaction area 1908. Therescaled color of reaction area 1908 would include the ambient lighteffect. Processor 112 then correlates the rescaled color and the ambientlight level detected in block 1814 (FIG. 18) to the analyte propertyusing a chart mapping rescaled color values and ambient light levels toanalyte property values. FIG. 24 illustrates one such chart 2400 inexamples of the present disclosure. In chart 2400, multiple linesrepresenting different analyte properties (e.g., blood glucose levels)plot color values over the ambient light levels. Such charts may beexperimentally determined for different mobile phones and stored withphotometric test strip analyzer 117 or downloaded as needed.

Referring back to FIG. 20, block 2016 may be followed by block 1628 ofmethod 1600.

FIG. 25 shows a variation 2500 of test strip module 100 (FIG. 1) inexamples of the present disclosure. FIG. 26 shows a partialcross-section of test strip module 100 in examples of the presentdisclosure. Test strip module 2500 has case 2502. The top of case 2502defines a finger guide 2504 and a sample collector 2506. A fluidtransport film 2508 is fixed to the top of case 2502 adjacent to samplecollector 2506. A lancet cover 2510 may be fitted to case 2502 tohermetically protect a lancet inside case 2502.

Sample collector 2506 may have the shape of a halved funnel. Fingerguide 2504 may be a V-shaped ramp with sidewalls that narrow toward theround edge of sample collector 2506, and the ramp slopes down toward theround edge of sample collector 2506. Fluid transport film 2508 abutsagainst the open half of the funnel shaped sample collector 2506. Inuse, user glides her finger along finger guide 2504 toward samplecollector 2506 and then deposit a sample in sample collector 2506.Referring to FIG. 26, the sample would collect at the bottom 2602 ofsample collector 2506. A hydrophilic layer 2604 on the back of fluidtransport film 2508 is located adjacent to the bottom 2602 of samplecollector 2506 and transports the sample laterally from bottom 2602 to achannel 2606 in case 2502. Channel 2606 is defined by case 2502 betweenhydrophilic layer 2604 and test strip 204. The sample travels fromhydrophilic layer 2604 down channel 2606 to test strip 204. Fluidtransport film 2508 may be Mylar with a hydrophilic coating 2604 on oneside.

From the foregoing, it will be appreciated that various embodiments ofthe present disclosure have been described herein for purposes ofillustration, and that various modifications may be made withoutdeparting from the scope and spirit of the present disclosure.Accordingly, the various embodiments disclosed herein are not intendedto be limiting, with the true scope and spirit being indicated by thefollowing claims.

We claim:
 1. A method for a mobile computing device to measure a teststrip in a test strip module, the method comprising: in a calibrationphase before a sample is introduced to a reaction area on the teststrip, detecting with a camera on a face of the mobile computing devicean ambient light effect from an ambient light leaking into the teststrip module through an interface between a case of the test stripmodule and the face of the mobile computing device when the test stripmodule is mounted on the face of the mobile computing device, whereindetecting the ambient light effect comprises: capturing a series ofimages under incrementing light intensities; linearizing a response ofthe camera based on the series; and determining a formula for acorrected color based a first image in the series that is captured withthe light source area off and a second in the series that is capturedwith the light source area on, comprising:${C_{corrected} = {\left( {C_{detected} - C_{on}} \right)\frac{C_{actual}}{C_{on} - C_{off}}}},{or}$${C_{corrected} = {\left( {C_{detected} - C_{off}} \right)\;\frac{c_{actual}}{C_{on} - C_{off}}}},$where C_(off) is a detected color of a color calibration area in thefirst image, C_(on) is a detected color of the color calibration area inthe second image, C_(actual) is an actual color of the color calibrationarea, C_(detected) is a detected color in a third image captured withthe light source area on in the measurement phase, and C_(corrected) isthe corrected color value; in a measurement phase after the sample isintroduced to the reaction area on the test strip: illuminating the teststrip with a light emitted by a light source area of a screen on theface of the mobile computing device, wherein the light source areacorresponds to a portion of the screen; detecting with the camera one ormore colors of the reaction area; correcting the detected one or morecolors for the ambient light effect; correlating the corrected one ormore colors to an analyte property; and displaying a value of theanalyte property on the screen.
 2. The method of claim 1, whereincorrecting the detected one or more colors for the ambient light effectincludes subtracting the ambient light effect from the detected color.3. The method of claim 1, wherein correlating the corrected one or morecolors to an analyte property comprises: determining a slope of a linebetween first and second points, the first point comprising a firstdetected color of a desired area and a first time at which the firstdetected color was captured in a first image during the measurementphase, the second point comprising a second detected color and a secondtime at which the second detected color was captured in a second imageduring the measurement phase; and correlating the slope to the value ofthe analyte property based on a chart.
 4. The method of claim 1, whereincorrelating the corrected one or more colors to an analyte propertycomprises: determining an ambient light level; determining a detectedcolor of a desired area captured in an image during the measurementphase; using a known color or known colors of a color calibration areaon the image to determine a rescaled color from the detected color; andcorrelating the ambient light level and the rescaled color to the valueof the analyte property based on a chart.
 5. The method of claim 1,further comprising performing a pre-test by: determining if an airplanemode of the mobile computing device is turned on, wherein the methodproceeds to the calibration and the measurement phases when the airplanemode is turned on; determining if a battery capacity is greater than afirst threshold, wherein the method proceeds to the calibration and themeasurement phases when the battery capacity is greater than the firstthreshold; determining if the mobile computing device is running on aninternal battery, wherein the method proceeds to the calibration and themeasurement phases when the mobile computing device is running on theinternal battery; or determining if an ambient light level is less thana second threshold, wherein the method proceeds to the calibration andthe measurement phases when the ambient light level is less than thesecond threshold.
 6. The method of claim 1, further comprising, prior tothe calibration phase: determining if the test strip is correctlypositioned, wherein the method proceeds to the calibration and themeasurement phases when the test strip is correctly positioned.
 7. Themethod of claim 6, wherein determining if the test strip is correctlypositioned comprises identifying the test strip in an image based on ashape, a color, or a light intensity.
 8. The method of claim 7, whereindetermining if the test strip is correctly positioned comprises furthercomprises taking a cross-section of a reaction area on the test strip inthe image and determining if sections of the cross-section have colorsthat correspond to actual colors of the reaction area.
 9. The method ofclaim 1, further comprising, in the calibration phase: determining ifthe ambient light effect is greater than a threshold; and when theambient light effect is greater than the threshold, displaying on thescreen a suggestion to move the mobile computing device or shield thetest strip module.
 10. The method of claim 9, wherein the suggestioncomprises shielding the test strip module with a hand or a box top thatis part of a packaging of the test strip module.
 11. The method of claim1, further comprising, before operating in the calibration phase and themeasurement phase, limiting any notification to a location away from thelight source area of the screen.
 12. The method of claim 11, whereinlimiting any notification comprises locking an orientation of the mobilecomputing device so notifications appear along one edge of the screeninstead of another edge that includes the light source area of thescreen.
 13. The method of claim 1, further comprising, locking a whitebalance for the camera by taking an image with low light immediatelybefore taking a second image with a light emitted by the light sourcearea of the screen.
 14. The method of claim 1, further comprising, inthe measurement phase, causing the mobile computing device to vibrate.